Nope.
Splitting water into free hydrogen and oxygen is important because it is an essential step for using electrical energy in the chemical and metallurgic industries.
For long term energy storage, free hydrogen is not a good solution, but it can be used to synthesize hydrocarbons, which are suitable for long term energy storage or for aerospace transportation.
Even with abundant and cheap dihydrogen, using it for energy storage in vehicles is a bad idea.
They said “delusional”
How does this refute the comment you replied to? That comment was implying that Toyota Mirai et al are ill-advised, so seems like your "nope" should be a "yep."